Systems, devices, and methods for optical waveguides

ABSTRACT

Systems, devices, and methods for optical waveguides that are well-suited for use in wearable heads-up displays (WHUDs) are described. An optical device comprises an optical waveguide including a volume of optically transparent material having a first longitudinal surface positioned opposite a second longitudinal surface across a width of the volume, an in-coupler, a liquid crystal out-coupler, and a controller to modulate a refractive index of the liquid crystal out-coupler. Light is in-coupled into the waveguide and is propagated along a length of the waveguide by total internal reflection between the longitudinal surfaces before being out-coupled by the liquid crystal out-coupler on a path that is dependent on the modulated refractive index of the liquid crystal out-coupler. In this way, light signals can be steered to create an image and/or to move an exit pupil of an image. WHUDs that employ such optical waveguides are also described.

TECHNICAL FIELD

The present systems, devices, and methods generally relate to steeringlight by optical waveguides, and particularly relate to systems,devices, and methods that employ such in wearable heads-up displays.

BACKGROUND Description of the Related Art Wearable Heads-Up Displays

A head-mounted display is an electronic device that is worn on a user'shead and, when so worn, secures at least one electronic display within aviewable field of at least one of the user's eyes, regardless of theposition or orientation of the user's head. A wearable heads-up displayis a head-mounted display that enables the user to see displayed contentbut also does not prevent the user from being able to see their externalenvironment. The “display” component of a wearable heads-up display iseither transparent or at a periphery of the user's field of view so thatit does not completely block the user from being able to see theirexternal environment. The “combiner” component of a wearable heads-updisplay is the physical structure where display light and environmentallight merge as one within the user's field of view. The combiner of awearable heads-up display is typically transparent to environmentallight but includes some optical routing mechanism to direct displaylight into the user's field of view.

Examples of wearable heads-up displays include: the Google Glass®, theOptinvent Ora®, the Epson Moverio®, and the Microsoft Hololens® just toname a few.

Optical Waveguides in Wearable Heads-Up Displays

A majority of currently available wearable heads-up displays employoptical waveguide systems in the transparent combiner. An opticalwaveguide operates under the principle of total internal reflection(TIR). TIR occurs when light remains in a first medium upon incidence ata boundary with a second medium because the refractive index of thefirst medium is greater than the refractive index of the second mediumand the angle of incidence of the light at the boundary is above aspecific critical angle that is a function of those refractive indices.Optical waveguides employed in wearable heads-up displays like thosementioned above consist of rectangular prisms of material with a higherrefractive index then the surrounding medium, usually air (GoogleGlass®, Optinvent Ora®, Epson Moverio®) or a planar lens (MicrosoftHololens®). Light input into the prism will propagate along the lengthof the prism as long as the light continues to be incident at boundariesbetween the prism and the surrounding medium at an angle above thecritical angle. Optical waveguides employ in-coupling and out-couplingto ensure that light follows a specific path along the optical waveguideand then exits the optical waveguide at a specific location and on aspecific path in order to create an image that is visible to the user.

The optical performance of a wearable heads-up display is an importantfactor in its design. When it comes to face-worn devices, however, usersalso care a lot about aesthetics. This is clearly highlighted by theimmensity of the eyeglass (including sunglass) frame industry.Independent of their performance limitations, many of the aforementionedexamples of wearable heads-up displays have struggled to find tractionin consumer markets because, at least in part, they lack fashion appeal.Visibility requirements of the displays of these current wearableheads-up displays necessitate larger display creation components. Mostwearable heads-up displays presented to date appear very bulky andunnatural on a user's face compared to the more sleek and streamlinedlook of typical curved eyeglass and sunglass lenses. There is a need inthe art for components which allow wearable heads-up displays to achievethe form factor and fashion appeal expected of the eyeglass frameindustry while creating a large, high quality display.

BRIEF SUMMARY

An optical device may be summarized as including: an optical waveguidecomprising volume of optically transparent material to propagate lightsignals by total internal reflection, wherein the volume of opticallytransparent material has a first longitudinal surface and a secondlongitudinal surface, the second longitudinal surface opposite the firstlongitudinal surface across a width of the volume of opticallytransparent material; an in-coupler; a liquid crystal out-coupler totunably steer light signals; and a controller communicatively coupled tothe liquid crystal out-coupler, wherein a refractive index of the liquidcrystal out-coupler is modulatable in response to signals from thecontroller. The liquid crystal out-coupler may comprise a singlemodulatable region or at least two distinct, independently modulatableregions.

The out-coupler may be a liquid crystal out-coupler communicativelycoupled to the controller and a refractive index of the out-coupler ismodulatable in response to signals from the controller to tunably steerthe light signals. The liquid crystal out-coupler may comprise a singlemodulatable region or at least two distinct, independently modulatableregions.

The optical device may further comprise a processor communicativelycoupled to the controller to modulate the output signals from thecontroller.

A method of operating an optical device comprising an optical waveguideincluding a volume of optically transparent material having a firstlongitudinal surface and a second longitudinal surface, the secondsurface positioned opposite the first surface across a width of thevolume of optically transparent material, an in-coupler, and a liquidcrystal out-coupler, and a controller communicatively coupled to theliquid crystal out-coupler, may be summarized as including: in-couplinga first set of light signals by the in-coupler; propagating the firstset of light signals along a length of the volume of opticallytransparent material by total internal reflection between the firstlongitudinal surface and the second longitudinal surface; modulating arefractive index of the liquid crystal out-coupler to a first refractiveindex by the controller; out-coupling the first set of light signals bythe liquid crystal out-coupler, wherein the first set of light signalsare output on a path that is dependent on the refractive index of theliquid crystal out-coupler. The method may further comprise: in-couplingthe second set of light signals by the in-coupler; propagating thesecond set of light signals along a length of the volume of opticallytransparent material by total internal reflection between the firstlongitudinal surface and the second longitudinal surface; modulating arefractive index of the liquid crystal out-coupler to a secondrefractive index by the controller; out-coupling the second set of lightsignals by the liquid crystal out-coupler region, wherein the second setof light signals are output on a path that is dependent on therefractive index of the liquid crystal out-coupler.

A wearable heads-up display (WHUD) may be summarized as including: asupport structure that in use is worn on the head of a user; a projectorto generate light signals, the projector comprising at least one lightsource; an optical waveguide comprising a volume of opticallytransparent material to propagate light signals by total internalreflection, wherein the volume of optically transparent material has afirst longitudinal surface and a second longitudinal surface, the secondlongitudinal surface opposite the first longitudinal surface across awidth of the volume of optically transparent material; an in-coupler; aliquid crystal out-coupler to tunably steer light signals; and acontroller communicatively coupled to the liquid crystal out-coupler,wherein a refractive index of the liquid crystal out-coupler ismodulatable in response to signals from the controller. The liquidcrystal out-coupler may comprise a single modulatable region or at leasttwo distinct, independently modulatable regions.

The out-coupler may be a liquid crystal out-coupler and wherein arefractive index of the out-coupler is modulatable in response tosignals from the controller to tunably steer the light signals. Theliquid crystal out-coupler may comprise a single modulatable region orat least two distinct, independently modulatable regions.

The WHUD may further comprise a processor communicatively coupled to theprojector to modulate the generation of light signals andcommunicatively coupled to the controller to modulate the output ofsignals from the controller.

The WHUD may further comprise a processor communicatively coupled to theprojector to modulate the generation of light signals.

The WHUD may further comprise a processor communicatively coupled to thecontroller to modulate the output of signals from the controller.

A method of operating a wearable heads-up display (WHUD) comprising asupport structure that in use is worn on the head of a user, a projectorwith at least one light source, an optical waveguide including a volumeof optically transparent material having a first longitudinal surfaceopposite a second longitudinal surface across a width of the volume ofoptically transparent material, an in-coupler, a liquid crystalout-coupler, and a controller communicatively coupled to the liquidcrystal out-coupler, may be summarized as including: generating a firstset of light signals by the at least one light source of the projector;in-coupling the second set of light signals into the volume of opticallytransparent material by the in-coupler; propagating the second set oflight signals along a length of the volume of optically transparentmaterial by total internal reflection between the first longitudinalsurface and the second longitudinal surface; modulating a refractiveindex of the liquid crystal out-coupler to a second refractive index bythe controller; out-coupling the second set of light signals by theliquid crystal out-coupler, wherein the second set of light signals areoutput on a path that is dependent on the refractive index of the liquidcrystal out-coupler. The method may further comprise: generating asecond set of light signals by the at least one light source of theprojector; in-coupling the second set of light signals into the volumeof optically transparent material by the in-coupler; propagating thesecond set of light signals along a length of the volume of opticallytransparent material by total internal reflection between the firstlongitudinal surface and the second longitudinal surface; modulating arefractive index of the liquid crystal out-coupler to a secondrefractive index by the controller; out-coupling the second set of lightsignals by the liquid crystal out-coupler, wherein the second set oflight signals are output on a path that is dependent on the refractiveindex of the liquid crystal out-coupler.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, identical reference numbers identify similar elementsor acts. The sizes and relative positions of elements in the drawingsare not necessarily drawn to scale. For example, the shapes of variouselements and angles are not necessarily drawn to scale, and some ofthese elements are arbitrarily enlarged and positioned to improvedrawing legibility. Further, the particular shapes of the elements asdrawn are not necessarily intended to convey any information regardingthe actual shape of the particular elements, and have been solelyselected for ease of recognition in the drawings.

FIG. 1A is a schematic diagram of an optical waveguide with a liquidcrystal in-coupler in accordance with the present systems, devices, andmethods.

FIG. 1B is a schematic diagram of an optical waveguide with a liquidcrystal in-coupler in accordance with the present systems, devices, andmethods.

FIG. 1C is a schematic diagram of an optical waveguide with a liquidcrystal in-coupler in accordance with the present systems, devices, andmethods.

FIG. 2A is a schematic diagram of an optical waveguide with a liquidcrystal out-coupler in accordance with the present systems, devices, andmethods.

FIG. 2B is a schematic diagram of an optical waveguide with a liquidcrystal out-coupler in accordance with the present systems, devices, andmethods.

FIG. 2C is a schematic diagram of an optical waveguide with a liquidcrystal out-coupler in accordance with the present systems, devices, andmethods.

FIG. 3A is a schematic diagram of an optical waveguide with a liquidcrystal in-coupler and a liquid crystal out-coupler in accordance withthe present systems, devices, and methods.

FIG. 3B is a schematic diagram of an optical waveguide with a liquidcrystal in-coupler and a liquid crystal out-coupler in accordance withthe present systems, devices, and methods.

FIG. 3C is a schematic diagram of an optical waveguide with a liquidcrystal in-coupler and a liquid crystal out-coupler in accordance withthe present systems, devices, and methods.

FIG. 3D is a schematic diagram of an optical waveguide with a liquidcrystal in-coupler and a liquid crystal out-coupler in accordance withthe present systems, devices, and methods.

FIG. 4 is a schematic diagram of an optical waveguide with a liquidcrystal in-coupler with multiple modulatable regions and a liquidcrystal out-coupler with multiple modulatable regions in accordance withthe present systems, devices, and methods.

FIG. 5 is a flow diagram of a method of operating an optical waveguidewith a liquid crystal in-coupler in accordance with the present systems,devices, and methods.

FIG. 6 is a flow diagram of a method of operating an optical waveguidewith a liquid crystal out-coupler in accordance with the presentsystems, devices, and methods.

FIG. 7 is a isometric view of a wearable heads-up display with anoptical waveguide with a liquid crystal in-coupler and a liquid crystalout-coupler in accordance with the present systems, devices, andmethods.

FIG. 8 is a schematic diagram of a wearable heads-up display with aprojector, a liquid crystal in-coupler with multiple modulatable regionsand a liquid crystal out-coupler with multiple modulatable regions inaccordance with the present systems, devices, and methods.

FIG. 9 is a flow diagram of a method of operating a wearable heads-updisplay with an optical waveguide with a liquid crystal in-coupler inaccordance with the present systems, devices, and methods.

FIG. 10 is a flow diagram of a method of operating a wearable heads-updisplay with an optical waveguide with a liquid crystal out-coupler inaccordance with the present systems, devices, and methods.

DETAILED DESCRIPTION

In the following description, certain specific details are set forth inorder to provide a thorough understanding of various disclosedembodiments. However, one skilled in the relevant art will recognizethat embodiments may be practiced without one or more of these specificdetails, or with other methods, components, materials, etc. In otherinstances, well-known structures associated with portable electronicdevices and head-worn devices, have not been shown or described indetail to avoid unnecessarily obscuring descriptions of the embodiments.

Unless the context requires otherwise, throughout the specification andclaims which follow, the word “comprise” and variations thereof, suchas, “comprises” and “comprising” are to be construed in an open,inclusive sense, that is as “including, but not limited to.”

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structures, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

As used in this specification and the appended claims, the singularforms “a,” “an,” and “the” include plural referents unless the contentclearly dictates otherwise. It should also be noted that the term “or”is generally employed in its broadest sense, that is as meaning “and/or”unless the content clearly dictates otherwise.

Throughout this specification the terms “in-coupler,” “out-coupler”“liquid crystal in-coupler,” “liquid crystal out-coupler,” “non-liquidcrystal in-coupler”, and non-liquid crystal out-coupler” are used. Thegeneric terms “in-coupler” and “out-coupler” may include any structureor optic that respectively in-couples or out-couples light, includingbut not limited to: a hologram, a holographic optical element, a volumediffraction grating, a surface relief grating, a transmission grating, areflection grating, or a liquid crystal element, liquid crystal cell orliquid crystal stack. The terms “liquid crystal in-coupler” and liquidcrystal out-coupler” refer to a modulatable liquid crystal element,modulatable liquid crystal cell or modulatable liquid crystal stack thatin use respectively in-couples light to or out-couples light from anoptical waveguide or slab. The terms “non-liquid crystal in-coupler” and“non-liquid crystal out-coupler” may include any element or optic thatrespectively in-couples light to or out-couples light from an opticalwaveguide or slab that does not include modulatable liquid crystalmaterial, and may refer to: a hologram, a holographic optical element, avolume diffraction grating, a surface relief grating, a transmissiongrating, or a reflection grating.

“In-coupling” and “out-coupling” of light signals into and out of awaveguide does not solely refer to light signals entering and exitingthe interior of the waveguide but also includes directing the lightsignals into and out of the waveguide on paths that enable the lightsignals to create the desired pattern upon exiting the waveguide. Thatis, an in-coupler or out-coupler does not only act to, respectively,input or output light signals while maintaining the current path of thelight signals, but instead may alter the direction of any or all lightsignals from the path of incidence on the in-coupler or out-coupler.

The propagation of light within the waveguides discussed throughout thisspecification is by total internal reflection (TIR). TIR occurs whenlight remains in a first medium (the waveguide) upon incidence at aboundary with a second medium because the refractive index of the firstmedium is greater than the refractive index of the second medium and theangle of incidence of the light at the boundary is above a specificcritical angle that is a function of those refractive indices.Throughout this specification when light signals are referred to aspropagating down the length of a waveguide it is meant that these lightsignals are propagated by total internal reflection and that the lightsignals have met the boundary between the material of the waveguide andthe medium external to the waveguide at or above the critical angle.

The headings and Abstract of the Disclosure provided herein are forconvenience only and do not interpret the scope or meaning of theembodiments.

FIG. 1A is a schematic diagram of an optical waveguide 100 a with aliquid crystal in-coupler 120 a in accordance with the systems, devices,and methods. Optical device 100 a includes a waveguide comprising avolume of optically transparent material 110 having a first longitudinalsurface 111 positioned opposite a second longitudinal surface 112 acrossa width 113 of volume of optically transparent material 110, liquidcrystal in-coupler 120 a, a controller (e.g., circuitry,micro-controller) 130 communicatively coupled to liquid crystalin-coupler 120 a, and a non-liquid crystal out-coupler 140.

Liquid crystal is a substance that exists between a liquid and a solidstate. The molecules of a solid substance are generally aligned whilemolecules in a liquid substance have no order. Molecules of a liquidcrystal may have some order but it is not uniform over the entiresubstance. Under external stimulation, e.g. an electric or magneticfield, the molecules of a liquid crystal can become ordered, which canresult in changes to the optical properties of the liquid crystal. Thisphenomenon provides a method of altering the refractive index of aliquid crystal element.

Optical device 100 a operates as follows. A first set of light signals150 a is incident on liquid crystal in-coupler 120 a (all arrowsrepresent the first set of light signals; only the first arrow in theset of arrows is labelled to reduce clutter). First set of light signals150 a may be a single light signal or may be multiple light signalswhich are incident on liquid crystal in-coupler 120 a simultaneously. InFIG. 1A, controller 130 has output a signal to modulate liquid crystalin-coupler 120 a to a first refractive index (represented by the shadingof liquid crystal in-coupler 120 a). Controller 130 may becommunicatively coupled to a processor (e.g., microprocessor) whichmodulates the output of signals from controller 130. The processor maybe communicatively coupled to a non-transitory processor-readablestorage medium (e.g., memory circuits such as ROM, RAM, FLASH, EEPROM,memory registers, magnetic disks, optical disks, other storage) and theprocessor may execute data and/or instruction from the non-transitoryprocessor readable storage medium to modulate controller 130. First setof light signals 150 a are in-coupled into volume of opticallytransparent material 110 by liquid crystal in-coupler 120 a. The paththat first set of light signals 150 a follows within volume of opticallytransparent material 110 is dependent on the refractive index of liquidcrystal in-coupler 120 a, and may be dependent on the wavelength of thelight signal(s), the angle of incidence of the light signal(s) on liquidcrystal in-coupler 120 a, and/or the location of incidence of the lightsignal(s) on liquid crystal in-coupler 120 a. First set of light signals150 a are propagated down the length of volume of optically transparentmaterial 110 by total internal reflection between first longitudinalsurface 111 and second longitudinal surface 112. First set of lightsignals 150 a are out-coupled by non-liquid crystal out-coupler 140 uponincidence of first set of light signals 150 a on out-coupler 140. InFIG. 1A, non-liquid crystal out-coupler 140 is located at or proximatesecond longitudinal surface 112 and first set of light signals 150 a areout-coupled by transmission, however, in another implementationnon-liquid crystal out-coupler 140 may be located elsewhere on or withinvolume of optically transparent material 110 and first set of lightsignals 150 a may be out-coupled by reflection. The output path(s) offirst set of lights signals 150 a may depend on the wavelength ofindividual light signals, the location of incidence of individual lightsignals on non-liquid crystal out-coupler 140, and the location ofincidence of individual light signals on non-liquid crystal out-coupler140. This process may be repeated for subsequent sets of light signals.If each set of light signals is a single light signal, an image or otherdesired pattern of light may be created by modulating the refractiveindex of the liquid crystal in-coupler to steer further sets of lightsignals as they are generated over time. That is, the refractive indexof the liquid crystal in-coupler may enable “scanning” of subsequentsingle light signals to create an image (e.g. raster scanning). If eachof light signals comprises multiple light signals, modulating therefractive index of the liquid crystal in-coupler may steer an exitpupil of an image (or portion of an image) or other desired patterncreated by the multiple light signals.

FIGS. 1B and 1C show examples of other refractive indices of the liquidcrystal in-coupler and the resulting out-coupling locations of the lightsignal(s).

FIG. 1B is a schematic diagram of an optical device 100 b with a liquidcrystal in-coupler 120 b in accordance with the present systems,devices, and methods. Optical device 100 b includes a waveguidecomprising a volume of optically transparent material 110 having a firstlongitudinal surface 111 positioned opposite a second longitudinalsurface 112 across a width 113 of volume of optically transparentmaterial 110, liquid crystal in-coupler 120 b, a controller (e.g.,circuitry, micro-controller) 130 communicatively coupled to liquidcrystal in-coupler 120 b, and a non-liquid crystal out-coupler 140.Optical device 100 b is the same as or similar to optical device 100 abut FIG. 1B shows a second set of light signals 150 b incident on liquidcrystal in-coupler 120 b which has a second refractive index. Opticaldevice 100 b operates as follows.

Second set of light signals 150 b is incident on liquid crystalin-coupler 120 b (all arrows represent the second set of light signals;only the first arrow in the set of arrows is labelled to reduceclutter). Second set of light signals 150 b may be a single light signalor may be multiple light signals which are incident on liquid crystalin-coupler 120 b simultaneously. In FIG. 1B, controller 130 has output asignal to modulate liquid crystal in-coupler 120 b to a secondrefractive index (represented by the shading of liquid crystalin-coupler 120 b). Second set of light signals 150 b are in-coupled intovolume of optically transparent material 110 by liquid crystalin-coupler 120 b. The path that second set of light signals 150 bfollows within volume of optically transparent material 110 is dependenton the refractive index of liquid crystal in-coupler 120 b, and may bedependent on the wavelength of the light signal(s), the angle ofincidence of the light signal(s) on liquid crystal in-coupler 120 b,and/or the location of incidence of the light signal(s) on liquidcrystal in-coupler 120 b. Second set of light signals 150 b arepropagated down the length of volume of optically transparent material110 by total internal reflection between first longitudinal surface 111and second longitudinal surface 112. Second set of light signals 150 bare out-coupled by non-liquid crystal out-coupler 140 upon incidence ofsecond set of light signals 150 b on non-liquid crystal out-coupler 140.The output path(s) of second set of lights signals 150 b may depend onthe wavelength of individual light signals, the location of incidence ofindividual light signals on non-liquid crystal out-coupler 140, and thelocation of incidence of individual light signals on non-liquid crystalout-coupler 140. The second refractive index of liquid crystalin-coupler 120 b causes second set of light signals 150 b to berefracted more than the first set of light signals 150 a and to travelfurther down the length of volume of optically transparent material 110before being out-coupled by non-liquid crystal out-coupler 140. In FIG.1B, non-liquid crystal out-coupler 140 is located at or proximate secondlongitudinal surface 112 and second set of light signals 150 b areout-coupled by transmission, however, in another implementationnon-liquid crystal out-coupler 140 may be located elsewhere on or withinvolume of optically transparent material 110 and second set of lightsignals 150 b may be out-coupled by reflection.

FIG. 1C is a schematic diagram of an optical device 100 c with a liquidcrystal in-coupler 120 c in accordance with the present systems,devices, and methods. Optical device 100 c includes a waveguidecomprising a volume of optically transparent material 110 having a firstlongitudinal surface 111 positioned opposite a second longitudinalsurface 112 across a width 113 of volume of optically transparentmaterial 110, liquid crystal in-coupler 120 c, a controller (e.g.,circuitry, micro-controller) 130 communicatively coupled to liquidcrystal in-coupler 120 c, and a non-liquid crystal out-coupler 140.Optical device 100 c is the same as or similar to optical device 100 aand optical device 100 b, but FIG. 1C shows a third set of light signals150 c incident on liquid crystal in-coupler 120 c which has a thirdrefractive index. Optical device 100 c operates as follows.

Third set of light signals 150 c is incident on liquid crystalin-coupler 120 c (all arrows represent the third set of light signals;only the first arrow in the set of arrows is labelled to reduceclutter). Third set of light signals 150 c may be a single light signalor may be multiple light signals which are incident on liquid crystalin-coupler 120 c simultaneously. In FIG. 1C, controller 130 has output asignal to modulate liquid crystal in-coupler 120 c to a third refractiveindex (represented by the shading of liquid crystal in-coupler 120 c).Third set of light signals 150 c are in-coupled into volume of opticallytransparent material 110 by liquid crystal in-coupler 120 c. The paththat third set of light signals 150 c follows within volume of opticallytransparent material 110 is dependent on the refractive index of liquidcrystal in-coupler 120 c, and may be dependent on the wavelength of thelight signal(s), the angle of incidence of the light signal(s) on liquidcrystal in-coupler 120 c, and/or the location of incidence of the lightsignal(s) on liquid crystal in-coupler 120 c. Third set of light signals150 c are propagated down the length of volume of optically transparentmaterial 110 by total internal reflection between first longitudinalsurface 111 and second longitudinal surface 112. Third set of lightsignals 150 c are out-coupled by non-liquid crystal out-coupler 140 uponincidence of third set of light signals 150 c on non-liquid crystalout-coupler 140. The output path(s) of third set of lights signals 150 cmay depend on the wavelength of individual light signals, the locationof incidence of individual light signals on non-liquid crystalout-coupler 140, and the location of incidence of individual lightsignals on non-liquid crystal out-coupler 140. The third refractiveindex of liquid crystal in-coupler 120 c causes third set of lightsignals 150 b to be refracted less than the first set of light signals150 a and to travel less distance down the length of volume of opticallytransparent material 110 before being out-coupled by non-liquid crystalout-coupler 140. In FIG. 1C, non-liquid crystal out-coupler 140 islocated at or proximate second longitudinal surface 112 and third set oflight signals 150 c are out-coupled by transmission, however, in anotherimplementation non-liquid crystal out-coupler 140 may be locatedelsewhere on or within volume of optically transparent material 110 andthird set of light signals 150 c may be out-coupled by reflection.

Throughout this specification and in the drawings, liquid crystalin-couplers or in-coupler are shown and discussed as being locatedparallel to the first longitudinal surface and the second longitudinalsurface of the volume of optically transparent material of thewaveguide. However, light signals may enter the volume of opticallytransparent material at an “end” of the volume of optically transparentmaterial, i.e., at a surface that is not along a length of the opticalwaveguide, and therefore the liquid crystal in-coupler or in-coupler mayalso be perpendicular to the length of the waveguide.

FIG. 2A is a schematic diagram of an optical device 200 a with a liquidcrystal out-coupler in accordance with the present systems, devices, andmethods. Optical device 200 a includes a waveguide comprising a volumeof optically transparent material 210 having a first longitudinalsurface 211 positioned opposite a second longitudinal surface 212 acrossa width 213 of volume of optically transparent material 210, anon-liquid crystal in-coupler 260, a liquid crystal out-coupler 270 a,and a controller (e.g., circuitry, micro-controller) 230 communicativelycoupled to liquid crystal in-coupler 270 a. Optical device 200 aoperates as follows.

A first set of light signals 250 a is incident on non-liquid crystalin-coupler 260 (all arrows represent the first set of light signals;only the first arrow in the set of arrows is labelled to reduceclutter). First set of light signals 250 a may be a single light signalor may be multiple light signals which are incident on non-liquidcrystal in-coupler 260 simultaneously. First set of light signals 250 aare in-coupled into volume of optically transparent material 210 bynon-liquid crystal in-coupler 260. The path that first set of lightsignals 250 a follows within volume of optically transparent material210 may be dependent on the wavelength of the light signal(s), the angleof incidence of the light signal(s) on non-liquid crystal in-coupler260, and/or the location of incidence of the light signal(s) onnon-liquid crystal in-coupler 260. First set of light signals 250 a arepropagated down the length of volume of optically transparent material210 by total internal reflection between first longitudinal surface 211and second longitudinal surface 212. First set of light signals 250 aare out-coupled by liquid crystal out-coupler 270 a upon incidence offirst set of light signals 250 a on liquid crystal out-coupler 270 a. InFIG. 2A, controller 230 has output a signal to modulate liquid crystalout-coupler 270 a to a first refractive index (represented by theshading of liquid crystal out-coupler 270 a). Controller 230 may becommunicatively coupled to a processor which modulates the output ofsignals from controller 230. The processor may be communicativelycoupled to a non-transitory processor-readable storage medium (e.g.,memory circuits such as ROM, RAM, FLASH, EEPROM, memory registers,magnetic disks, optical disks, other storage) and the processor mayexecute data and/or instruction from the non-transitory processorreadable storage medium to modulate controller 230. In FIG. 2A, liquidcrystal out-coupler 270 a is located at or proximate second longitudinalsurface 212 and first set of light signals 250 a are out-coupled bytransmission, however, in another implementation liquid crystalout-coupler 270 a may be located elsewhere on or within volume ofoptically transparent material 210 and first set of light signals 250 amay be out-coupled by reflection. The output path of first set of lightssignals 250 a may also depend on the wavelength of individual lightsignals, the location of incidence of individual light signals on liquidcrystal out-coupler 270 a, and the location of incidence of individuallight signals on liquid crystal out-coupler 270 a. If first set of lightsignals 250 a is a single light signal, an image or other desiredpattern of light may be created by modulating the refractive index ofliquid crystal out-coupler 270 a over time to steer a single beam overtime. This process may be repeated for subsequent sets of light signals.If each set of light signals is a single light signal, an image or otherdesired pattern of light may be created by modulating the refractiveindex of the liquid crystal in-coupler to steer further sets of lightsignals as they are generated over time. That is, the refractive indexof the liquid crystal in-coupler may enable “scanning” of subsequentsingle light signals to create an image (e.g. raster scanning). If eachof light signals comprises multiple light signals, modulating therefractive index of the liquid crystal in-coupler may steer an exitpupil of an image (or portion of an image) or other desired patterncreated by the multiple light signals.

FIG. 2B is a schematic diagram of an optical device 200 b with a liquidcrystal out-coupler in accordance with the present systems, devices, andmethods. Optical device 200 b includes a waveguide comprising a volumeof optically transparent material 210 having a first longitudinalsurface 211 positioned opposite a second longitudinal surface 212 acrossa width 213 of volume of optically transparent material 210, anon-liquid crystal in-coupler 260, a liquid crystal out-coupler 270 b,and a controller (e.g., circuitry, micro-controller) 230 communicativelycoupled to liquid crystal in-coupler 270 b. Optical device 200 b is thesame as or similar to optical device 200 a but FIG. 2B shows a secondset of light signals 250 b incident and liquid crystal out-coupler 270 bhas a second refractive index. Optical device 200 b operates as follows.

A second set of light signals 250 b is incident on non-liquid crystalin-coupler 260 (all arrows represent the second set of light signals;only the first arrow in the set of arrows is labelled to reduceclutter). Second set of light signals 250 b may be a single light signalor may be multiple light signals which are incident on non-liquidcrystal in-coupler 260 simultaneously. Second set of light signals 250 bare in-coupled into volume of optically transparent material 210 bynon-liquid crystal in-coupler 260. The path that second set of lightsignals 250 b follows within volume of optically transparent material210 may be dependent on the wavelength of the light signal(s), the angleof incidence of the light signal(s) on non-liquid crystal in-coupler260, and/or the location of incidence of the light signal(s) onnon-liquid crystal in-coupler 260. Second set of light signals 250 b arepropagated down the length of volume of optically transparent material210 by total internal reflection between first longitudinal surface 211and second longitudinal surface 212. Second set of light signals 250 bare out-coupled by liquid crystal out-coupler 270 b upon incidence ofsecond set of light signals 250 b on liquid crystal out-coupler 270 b.In FIG. 2B, controller 230 has output a signal to modulate liquidcrystal out-coupler 270 b to a second refractive index (represented bythe shading of liquid crystal out-coupler 270 b). Second set of lightsignals 250 b are out-coupled from optical device 200 b on a differentpath than light signals 250 a in FIG. 1A, the output path dependent onthe second refractive index of liquid crystal out-coupler 270 b. Theoutput path of second set of lights signals 250 b may also depend on thewavelength of individual light signals, the location of incidence ofindividual light signals on liquid crystal out-coupler 270 b, and thelocation of incidence of individual light signals on liquid crystalout-coupler 270 b. In FIG. 2B, liquid crystal out-coupler 270 b islocated at or proximate second longitudinal surface 212 and second setof light signals 250 b are out-coupled by transmission, however, inanother implementation liquid crystal out-coupler 270 b may be locatedelsewhere on or within volume of optically transparent material 210 andsecond set of light signals 250 b may be out-coupled by reflection.

FIG. 2C is a schematic diagram of an optical device 200 c with a liquidcrystal out-coupler in accordance with the present systems, devices, andmethods. Optical device 200 c includes a waveguide comprising a volumeof optically transparent material 210 having a first longitudinalsurface 211 positioned opposite a second longitudinal surface 212 acrossa width 213 of volume of optically transparent material 210, anon-liquid crystal in-coupler 260, a liquid crystal out-coupler 270 c,and a controller (e.g., circuitry, micro-controller) 230 communicativelycoupled to liquid crystal in-coupler 270 c. Optical device 200 c is thesame as or similar to optical device 200 a and optical device 200 b butFIG. 2C shows a third set of light signals 250 c incident and liquidcrystal out-coupler 270 c has a second refractive index. Optical device200 c operates as follows.

A third set of light signals 250 c is incident on non-liquid crystalin-coupler 260 (all arrows represent the first set of light signals;only the first arrow in the set of arrows is labelled to reduceclutter). Third set of light signals 250 c may be a single light signalor may be multiple light signals which are incident on non-liquidcrystal in-coupler 260 simultaneously. Third set of light signals 250 care in-coupled into volume of optically transparent material 210 bynon-liquid crystal in-coupler 260. The path that third set of lightsignals 250 c follows within volume of optically transparent material210 may be dependent on the wavelength of the light signal(s), the angleof incidence of the light signal(s) on non-liquid crystal in-coupler260, and/or the location of incidence of the light signal(s) onnon-liquid crystal in-coupler 260. Third set of light signals 250 c arepropagated down the length of volume of optically transparent material210 by total internal reflection between first longitudinal surface 211and third longitudinal surface 212. Third set of light signals 250 c areout-coupled by liquid crystal out-coupler 270 c upon incidence of thirdset of light signals 250 c on liquid crystal out-coupler 270 c. In FIG.2C, controller 230 has output a signal to modulate liquid crystalout-coupler 270 c to a third refractive index (represented by theshading of liquid crystal out-coupler 270 c). Third set of light signals250 c are out-coupled from optical device 200 c on a different path thanlight signals 250 a and light signals 250 b in FIGS. 1A and 1B, theoutput path dependent on the third refractive index of liquid crystalout-coupler 270 c. The output path of third set of lights signals 250 cmay also depend on the wavelength of individual light signals, thelocation of incidence of individual light signals on liquid crystalout-coupler 270 c, and the location of incidence of individual lightsignals on liquid crystal out-coupler 270 c. In FIG. 2C, liquid crystalout-coupler 270 c is located at or proximate second longitudinal surface212 and third set of light signals 250 c are out-coupled bytransmission, however, in another implementation liquid crystalout-coupler 270 c may be located elsewhere on or within volume ofoptically transparent material 210 and third set of light signals 250 cmay be out-coupled by reflection.

FIG. 3A is a schematic diagram of an optical device 300 a with a liquidcrystal in-coupler 320 a and a liquid crystal out-coupler 370 a inaccordance with the present systems, devices, and methods. Opticaldevice 300 a includes a waveguide comprising a volume of opticallytransparent material 310 having a first longitudinal surface 311positioned opposite a second longitudinal surface 312 across a width 313of volume of optically transparent material 310, a liquid crystalin-coupler 320 a, a liquid crystal out-coupler 370 a, and a controller(e.g., circuitry, micro-controller) 330 communicatively coupled to bothliquid crystal in-coupler 320 a and liquid crystal out-coupler 370 a.Optical device 300 a operates as follows.

A first set of light signals 350 a is incident on liquid crystalin-coupler 320 a (all arrows represent the first set of light signals;only the first arrow in the set of arrows is labelled to reduceclutter). First set of light signals 350 a may be a single light signalor may be multiple light signals which are incident on liquid crystalin-coupler 320 a simultaneously. In FIG. 3A, controller 330 has output asignal to modulate liquid crystal in-coupler 320 a to a first refractiveindex (represented by the shading of liquid crystal in-coupler 320 a).First set of light signals 350 a are in-coupled into volume of opticallytransparent material 310 by liquid crystal in-coupler 320 a. The paththat first set of light signals 350 a follows within volume of opticallytransparent material 310 is dependent on the refractive index of liquidcrystal in-coupler 320 a, and may be dependent on the wavelength of thelight signal(s), the angle of incidence of the light signal(s) on liquidcrystal in-coupler 320 a, and/or the location of incidence of the lightsignal(s) on liquid crystal in-coupler 320 a. First set of light signals350 a are propagated down the length of volume of optically transparentmaterial 310 by total internal reflection between first longitudinalsurface 311 and second longitudinal surface 312. In FIG. 3A, controller330 has output a signal to modulate liquid crystal out-coupler 370 a toa first refractive index (the first refractive index of liquid crystalin-coupler 320 a and the first refractive index of liquid crystalout-coupler 370 a may be the same or may be different refractiveindices; the first refractive index of liquid crystal out-coupler 370 ais represented by shading). Controller 330 may be communicativelycoupled to a processor (e.g., microprocessor) which modulates the outputof signals from controller 330. The processor may be communicativelycoupled to a non-transitory processor-readable storage medium (e.g.,memory circuits such as ROM, RAM, FLASH, EEPROM, memory registers,magnetic disks, optical disks, other storage) and the processor mayexecute data and/or instruction from the non-transitory processorreadable storage medium to modulate controller 330. First set of lightsignals 350 a are out-coupled by liquid crystal out-coupler 370 a uponincidence of first set of light signals 350 a on liquid crystalout-coupler 370 a. The output path of first set of light signals 350 afrom optical device 300 a is dependent on the refractive index of liquidcrystal out-coupler 370 a, and may be dependent on the wavelength of thelight signal(s), the angle of incidence of the light signal(s) on liquidcrystal out-coupler 370 a, and/or the location of incidence of the lightsignal(s) on liquid crystal out-coupler 370 a. This process may berepeated for subsequent sets of light signals. If each set of lightsignals is a single light signal, an image or other desired pattern oflight may be created by modulating the refractive index of the liquidcrystal in-coupler to steer further sets of light signals as they aregenerated over time. That is, the refractive index of the liquid crystalin-coupler may enable “scanning” of subsequent single light signals tocreate an image (e.g., raster scanning). If each of light signalscomprises multiple light signals, modulating the refractive index of theliquid crystal in-coupler may steer an exit pupil of an image (orportion of an image) or other desired pattern created by the multiplelight signals.

FIGS. 3B, 3C, and 3D show other examples of modulating the respectiverefractive indices of the liquid crystal in-coupler and the liquidcrystal out-coupler and the resulting out-coupling locations of thelight signal(s).

FIG. 3B is a schematic diagram of an optical device 300 b with a liquidcrystal in-coupler 320 b and a liquid crystal out-coupler 370 b inaccordance with the present systems, devices, and methods. Opticaldevice 300 b includes a waveguide comprising a volume of opticallytransparent material 310 having a first longitudinal surface 311positioned opposite a second longitudinal surface 312 across a width 313of volume of optically transparent material 310, a liquid crystalin-coupler 320 b, a liquid crystal out-coupler 370 b, and a controller(e.g., circuitry, micro-controller) 330 communicatively coupled to bothliquid crystal in-coupler 320 b and liquid crystal out-coupler 370 b.Optical device 300 b is the same as or similar to optical device 300 abut a second set of light signals 350 b is shown and liquid crystalin-coupler 320 b has a second refractive index. Optical device 300 boperates as follows.

A second set of light signals 350 b is incident on liquid crystalin-coupler 320 b (all arrows represent the second set of light signals;only the first arrow in the set of arrows is labelled to reduceclutter). Second set of light signals 350 b may be a single light signalor may be multiple light signals which are incident on liquid crystalin-coupler 320 b simultaneously. In FIG. 3B, controller 330 has output asignal to modulate liquid crystal in-coupler 320 b to a secondrefractive index (represented by the shading of liquid crystalin-coupler 320 b). Second set of light signals 350 b are in-coupled intovolume of optically transparent material 310 by liquid crystalin-coupler 320 b. The path that second set of light signals 350 bfollows within volume of optically transparent material 310 is dependenton the refractive index of liquid crystal in-coupler 320 b, and may bedependent on the wavelength of the light signal(s), the angle ofincidence of the light signal(s) on liquid crystal in-coupler 350 b,and/or the location of incidence of the light signal(s) on liquidcrystal in-coupler 350 b. Second set of light signals 350 b arepropagated down the length of volume of optically transparent material310 by total internal reflection between first longitudinal surface 311and second longitudinal surface 312. In FIG. 3B, controller 330 hasoutput a signal to modulate liquid crystal out-coupler 370 b to thefirst refractive index. Second set of light signals 350 b areout-coupled by liquid crystal out-coupler 370 b upon incidence of secondset of light signals 350 b on liquid crystal out-coupler 370 b. Theoutput path of second set of light signals 350 b from optical device 300b is dependent on the refractive index of liquid crystal out-coupler 370b. The output path of second set of lights signals 350 b may also dependon the wavelength of individual light signals, the location of incidenceof individual light signals on liquid crystal out-coupler 370 b, and thelocation of incidence of individual light signals on liquid crystalout-coupler 370 b. Because second set of light signals 350 b passedthrough the second refractive index of liquid crystal in-coupler 320 binstead of first refractive index of liquid crystal in-coupler 320 a,light signals 350 b travel further down the length of volume ofoptically transparent material 310 before being output.

FIG. 3C is a schematic diagram of an optical device 300 c with a liquidcrystal in-coupler 320 c and a liquid crystal out-coupler 370 c inaccordance with the present systems, devices, and methods. Opticaldevice 300 c includes a waveguide comprising a volume of opticallytransparent material 310 having a first longitudinal surface 311positioned opposite a second longitudinal surface 312 across a width 313of volume of optically transparent material 310, a liquid crystalin-coupler 320 c, a liquid crystal out-coupler 370 c, and a controller(e.g., circuitry, micro-controller) 330 communicatively coupled to bothliquid crystal in-coupler 320 c and liquid crystal out-coupler 370 c.Optical device 300 c is the same as or similar to optical device 300 aand optical device 300 b but a third set of light signals 350 c is shownand liquid crystal out-coupler 370 c has a second refractive index.Optical device 300 c operates as follows.

A third set of light signals 350 c is incident on liquid crystalin-coupler 320 c (all arrows represent the third set of light signals;only the first arrow in the set of arrows is labelled to reduceclutter). Third set of light signals 350 c may be a single light signalor may be multiple light signals which are incident on liquid crystalin-coupler 320 c simultaneously. In FIG. 3C, controller 330 has output asignal to modulate liquid crystal in-coupler 320 c to the firstrefractive index (represented by the shading of liquid crystalin-coupler 320 c). Third set of light signals 350 c are in-coupled intovolume of optically transparent material 310 by liquid crystalin-coupler 320 c. The path that third set of light signals 350 c followswithin volume of optically transparent material 310 is dependent on therefractive index of liquid crystal in-coupler 320 c, and may bedependent on the wavelength of the light signal(s), the angle ofincidence of the light signal(s) on liquid crystal in-coupler 320 c,and/or the location of incidence of the light signal(s) on liquidcrystal in-coupler 320 c. Third set of light signals 350 c arepropagated down the length of volume of optically transparent material310 by total internal reflection between first longitudinal surface 311and second longitudinal surface 312. In FIG. 3C, controller 330 hasoutput a signal to modulate liquid crystal out-coupler 370 c to a secondrefractive index. Third set of light signals 350 c are out-coupled byliquid crystal out-coupler 370 c upon incidence of third set of lightsignals 350 c on liquid crystal out-coupler 370 c. The output path ofthird set of light signals 350 c from optical device 300 c is dependenton the refractive index of liquid crystal out-coupler 370 c. The outputpath of third set of lights signals 350 c may also depend on thewavelength of individual light signals, the location of incidence ofindividual light signals on liquid crystal out-coupler 370 c, and thelocation of incidence of individual light signals on liquid crystalout-coupler 370 c. Because third set of light signals 350 c passedthrough the second refractive index of liquid crystal out-coupler 370 binstead of first refractive index of liquid crystal out-coupler 370 a,light signals 350 c exit waveguide 300 c at the same location as firstset of light signals 350 a, but at an angle further from perpendicularto second longitudinal surface 312 than both light signals 350 a and 350b.

FIG. 3D is a schematic diagram of an optical device 300 d with a liquidcrystal in-coupler 320 d and a liquid crystal out-coupler 370 d inaccordance with the present systems, devices, and methods. Opticaldevice 300 d includes a waveguide comprising a volume of opticallytransparent material 310 having a first longitudinal surface 311positioned opposite a second longitudinal surface 312 across a width 313of volume of optically transparent material 310, a liquid crystalin-coupler 320 d, a liquid crystal out-coupler 370 d, and a controller(e.g., circuitry, micro-controller) 330 communicatively coupled to bothliquid crystal in-coupler 320 d and liquid crystal out-coupler 370 d.Optical device 300 d is the same as or similar to optical device 300 a,optical device 300 b, and optical device 300 c but a fourth set of lightsignals 350 d is shown and both liquid crystal in-coupler 320 d andliquid crystal out-coupler 370 d have a respective second refractiveindices. Optical device 300 a operates as follows.

A fourth set of light signals 350 d is incident on liquid crystalin-coupler 320 d (all arrows represent the fourth set of light signals;only the first arrow in the set of arrows is labelled to reduceclutter). Fourth set of light signals 350 d may be a single light signalor may be multiple light signals which are incident on liquid crystalin-coupler 320 d simultaneously. In FIG. 3D, controller 330 has output asignal to modulate liquid crystal in-coupler 320 d to the secondrefractive index (represented by the shading of liquid crystalin-coupler 320 d). Fourth set of light signals 350 d are in-coupled intovolume of optically transparent material 310 by liquid crystalin-coupler 320 d. The path that fourth set of light signals 350 dfollows within volume of optically transparent material 310 is dependenton the refractive index of liquid crystal in-coupler 320 d, and may bedependent on the wavelength of the light signal(s), the angle ofincidence of the light signal(s) on liquid crystal in-coupler 320 d,and/or the location of incidence of the light signal(s) on liquidcrystal in-coupler 320 d. Fourth set of light signals 350 d arepropagated down the length of volume of optically transparent material310 by total internal reflection between first longitudinal surface 311and second longitudinal surface 312. In FIG. 3D, controller 330 hasoutput a signal to modulate liquid crystal out-coupler 370 d to a secondrefractive index. Fourth set of light signals 350 d are out-coupled byliquid crystal out-coupler 370 d upon incidence of fourth set of lightsignals 350 d on liquid crystal out-coupler 370 d. The output path offourth set of light signals 350 d from optical device 300 d is dependenton the refractive index of liquid crystal out-coupler 370 d. The outputpath of third set of lights signals 350 d may also depend on thewavelength of individual light signals, the location of incidence ofindividual light signals on liquid crystal out-coupler 370 d, and thelocation of incidence of individual light signals on liquid crystalout-coupler 370 d. Because fourth set of light signals 350 c passedthrough the second refractive index of liquid crystal in-coupler 320 dinstead of first refractive index of liquid crystal in-couplers 320 aand 320 c, and also passed through the second refractive index of liquidcrystal out-coupler 370 d instead of the refractive index of liquidcrystal out-couplers 370 a and 370 b, fourth set of light signals 350 dexit waveguide 300 d at the same location as second set of light signals350 a, but at an angle further from perpendicular to second longitudinalsurface 312 than light signals 350 a, and 350 b.

FIG. 4 is a schematic diagram of an optical device 400 with a liquidcrystal in-coupler 420 with multiple modulatable regions 421, 422, and423 and a liquid crystal out-coupler 470 with multiple modulatableregions 471, 472, and 473 in accordance with the present systems,devices, and methods. FIGS. 1, 2, and 3 all show liquid crystalin-couplers and/or liquid crystal out-couplers with only one modulatableregion. However, both liquid crystal in-couplers and liquid crystalout-couplers could include at least two distinct, independentlymodulatable regions. Optical device 400 includes a waveguide comprisinga volume of optically transparent material 410 having a firstlongitudinal surface 411 positioned opposite a second longitudinalsurface 412 across a width 413 of volume of optically transparentmaterial 410, a liquid crystal in-coupler 420 with multiple modulatableregions 421, 422, and 423, a liquid crystal out-coupler 470 withmultiple modulatable regions 471, 472, and 473, and a controller (e.g.,circuitry, micro-controller) 430 communicatively coupled to both liquidcrystal in-coupler 420 and liquid crystal out-coupler 470. Controller430 modulates each of modulatable regions 421, 422, and 423,independently and may be separately communicatively coupled to eachmodulatable region (controller 430 is shown as having only one couplingto each of liquid crystal in-coupler 420 and liquid crystal out-coupler470 to reduce clutter). Controller 430 is shown in this configurationsolely for clarity and in an actual implementation would not be solocated. Controller 430 may be communicatively coupled to a processor(e.g., microprocessor) which modulates the output of signals fromcontroller 430. The processor may be communicatively coupled to anon-transitory processor-readable storage medium (e.g., memory circuitssuch as ROM, RAM, FLASH, EEPROM, memory registers, magnetic disks,optical disks, other storage) and the processor may execute data and/orinstruction from the non-transitory processor readable storage medium tomodulate controller 430. Optical device 400 operates as follows.

Light signals 451 (solid line arrows), 452 (dashed line arrows) and 453(dashed and dotted line arrows) are incident on liquid crystalin-coupler 420 (only the first arrow for each light signal is labelledto reduce clutter). Liquid crystal in-coupler 420 has threeindependently modulatable regions. Each of light signals 451, 452, and453 are incident on a respective one of modulatable regions 421, 422,and 423 of liquid crystal in-coupler 420. In FIG. 4, controller 430 hasmodulated each modulatable region of liquid crystal in-coupler 420 tohave the same refractive index and therefore light signals 451, 452, and453 which are incident on liquid crystal in-coupler 420 at the sameangle but at different locations are in-coupled into volume of opticallytransparent material 410 on paths with identical angles but differentlocations. Modulatable regions 421, 422, and 423 of liquid crystalin-coupler 420 may be modulated by controller 430 to have differentrefractive indices. Light signals 451, 452, and 453 are propagated alongoptical device 400 by total internal reflection between firstlongitudinal surface 411 and second longitudinal surface 412. Lightsignals 451, 452, and 453 are incident on liquid crystal out-coupler470. Each of light signals 451, 452, and 453 are incident on arespective one of modulatable regions 471, 472, and 473 of liquidcrystal out-coupler 470. In FIG. 4, modulatable regions 471, 472, and473 of liquid crystal out-coupler 470 has been modulated by controller430 to have different refractive indices and therefore light signals451, 452, and 453 which are incident on liquid crystal in-coupler 470 atthe same angle but at different location are out-coupled towards a useron paths with different angles. Independently modulating the regions ofliquid crystal in-coupler 420 and/or liquid crystal out-coupler 470enables more freedom in image creation both spatially and temporally. Asin earlier figures, light signals 451, 452, and 453 are only exemplaryand may each be representative of multiple light signals. The relativedimensions of liquid crystal in-coupler 420, liquid crystal out-coupler470, and their respective modulatable regions are exemplary and are notnecessarily representative of actual dimensions. In otherimplementations, only one of liquid crystal in-coupler 420 or liquidcrystal out-coupler 470 may have multiple modulatable regions. In otherimplementations, each independently modulatable region of liquid crystalin-coupler 420 or liquid crystal out-coupler 470 may have a respectivecontroller.

In other implementations, a liquid crystal out-coupler with a singlemodulatable region or individual modulatable regions of a liquid crystalout-coupler like liquid crystal out-coupler 470 may be modulated bycontroller 430 to be opaque. By modulating a region of the liquidcrystal out-coupler to be opaque, a light signal or multiple lightsignals when incident on the opaque region will reflect back into thevolume of optically transparent material and propagate further down thewaveguide before being out-coupled. In the case of a single regionliquid crystal out-coupler, the liquid crystal out-coupler would need tobe modulated from opaque to transmissive before the second incidence ofthe light signal on the out-coupler. In the case of a liquid crystalout-coupler with multiple independently modulatable regions, the regionwhere the incidence first occurs will be modulated to opaque while theregion where the second incidence occurs will be modulated to betransmissive (depending on the size of the regions, the regions of firstand second incidence may be the same region or different regions).

In other implementations, each of liquid crystal in-coupler 420 andliquid crystal out-coupler 470 may be modulated by a distinct controllerinstead of the same controller.

FIG. 5 is a flow diagram of a method 500 of operating an optical devicewith a liquid crystal in-coupler in accordance with the present systems,devices, and methods. The optical device of FIG. 5 may be similar tooptical devices 100 a, 100 b, and 100 c from FIG. 1. For example, theoptical device may include a waveguide comprising a volume of opticallytransparent material having a first longitudinal surface positionedopposite a second longitudinal surface across a width of volume ofoptically transparent material, a liquid crystal in-coupler, acontroller communicatively coupled to the liquid crystal in-coupler, andan out-coupler. Method 500 includes acts 501, 502, 503, and 504, thoughthose of skill in the art will appreciate that in alternativeembodiments certain acts may be omitted and/or additional acts may beadded. Those of skill in the art will also appreciate that theillustrated order of the acts is shown for exemplary purposes only andmay change in alternative embodiment.

At 501, a refractive index of the liquid crystal in-coupler is modulatedto a first refractive index by the controller. The controller maymodulate the refractive index of the liquid crystal in-coupler byaltering a voltage (or another modulating signal) applied to the liquidcrystal in-coupler. The liquid crystal may operate in a positive modewherein a higher voltage results in a higher opacity, or a negative modewherein a higher voltage results in a lower opacity. The liquid crystalin-coupler may comprise multiple independently modulatable regions whichmay be modulated by the controller to each have a respective firstrefractive index, wherein the refractive index of each respective regionmay be different from or the same as the refractive indices of the otherregions. The controller may be communicatively coupled to a processorwhich modulates the output of signals from the controller. The processormay be communicatively coupled to a non-transitory processor-readablestorage medium and the processor may execute data and/or instructionfrom the non-transitory processor readable storage medium to modulatethe controller. Notably, the modulation of the refractive index of theliquid crystal in-coupler can occur just before or during incidence oflight signals, and will in many instances be concurrent or evensimultaneous.

At 502, a first set of light signals is in-coupled into the volume ofoptically transparent material of the waveguide, wherein a path (orpaths) of the first set of light signals within the volume of opticallytransparent material is dependent on the first refractive index of theliquid crystal in-coupler. That is, the path of the light signals isaltered (or remains unaltered) in response to the refractive index ofthe liquid crystal in-coupler, resulting in the light signals beingsteered by the liquid crystal in-coupler. The path of an individuallight signal may also be dependent on the wavelength of the lightsignal, the location of incidence of the light signal on the liquidcrystal in-coupler, and/or the angle of incidence of the light signal onthe liquid crystal in-coupler. The light signals are in-coupled on apath that will eventually result in a desired image or part of an imageat the desired location, for example at an eye of a user. If the liquidcrystal in-coupler comprises multiple independently modulatable regionsthe path of an individual light signal is dependent on the modulatableregion upon which the individual light signal is incident. The liquidcrystal in-coupler may be present on the exterior of the volume ofoptically transparent material or may be located inside the volume ofoptically transparent material. If located inside the volume ofoptically transparent material, the liquid crystal in-coupler may be ator proximate the first longitudinal surface of the second longitudinalsurface, or may be embedded within the volume of optically transparentmaterial not at or proximate a surface.

At 503, the first set of light signals are propagated along a length ofthe volume of optically transparent material by total internalreflection between the first longitudinal surface and the secondlongitudinal surface.

At 504, the first set of light signals are output from the waveguide bythe out-coupler. The first set of light signals are output from theoptical waveguide on a path that creates the desired image or part of animage at the desired location. The output path of an individual lightsignal may depend on the wavelength of the light signal, the location ofincidence of the light signal on the out-coupler, and/or the angle ofincidence of the light signals on the out-coupler. The out-coupler maybe at or proximate the first longitudinal surface and may out-couple thefirst set of light signals by reflection or the out-coupler may be at orproximate the second longitudinal surface and may out-couple the firstset of light signals by transmission.

Method 500 may further include repeating acts 501, 502, 503, 504, and505 with a second set of light signals, wherein the controller modulatesthe liquid crystal in-coupler to have a second refractive index, or ifthe liquid crystal in-coupler has multiple independently modulatableregions, a second set of refractive indices. This may be repeated forother sets of light signals. If each set of light signals is a singlelight signal, an image or other desired pattern of light may be createdby modulating the refractive index of the liquid crystal in-coupler tosteer further sets of light signals as they are generated over time.That is, the refractive index of the liquid crystal in-coupler mayenable “scanning” of subsequent single light signals to create an image(e.g. raster scanning). If each set of light signals comprises multiplelight signals, modulating the refractive index of the liquid crystalin-coupler may steer an exit pupil of an image (or portion of an image)or other desired pattern created by the multiple light signals.

In some implementations, the out-coupler may be a liquid crystalout-coupler which is communicatively coupled to the controller (or maybe communicatively coupled to a second, distinct controller) and themethod may further include modulating the refractive index of the liquidcrystal out-coupler to a third refractive index (the third refractiveindex may be the same as either the first or second refractive index andmay be different from both the first or second refractive index) andout-coupling a set of light signals on output path(s) which aredependent on the refractive index of the liquid crystal out-coupler. Theoutput paths of the light signals may also be dependent on thewavelength of the light signals, the location of incidence of the lightsignals on the liquid crystal out-coupler, and/or the angle of incidenceof the light signals on the liquid crystal out-coupler.

FIG. 6 is a flow diagram of a method of operating an optical waveguidewith a liquid crystal out-coupler in accordance with the presentsystems, devices, and methods. The optical device of FIG. 6 may besimilar to optical devices 200 a, 200 b, and 200 c from FIG. 1. Theoptical device includes a waveguide comprising a volume of opticallytransparent material having a first longitudinal surface positionedopposite a second longitudinal surface across a width of volume ofoptically transparent material, an in-coupler, a liquid crystalout-coupler, and a controller communicatively coupled to the liquidcrystal out-coupler. Method 600 includes acts 601, 602, 603, and 604,though those of skill in the art will appreciate that in alternativeembodiments certain acts may be omitted and/or additional acts may beadded. Those of skill in the art will also appreciate that theillustrated order of the acts is shown for exemplary purposes only andmay change in alternative embodiment.

At 601, a first set of light signals are in-coupled into the waveguideby the in-coupler. That is, the first set of light signals arein-coupled into the volume of optically transparent material on thedesired path to eventually create a desired image or part of an image ata desired location, for example an eye of a user. The path of anindividual light signal may depend on the wavelength of the lightsignal, the location of incidence of the light signal on the in-coupler,and/or the angle of incidence of the light signals on the in-coupler.The in-coupler may be at or proximate the first longitudinal surface andmay in-couple the first set of light signals by reflection or thein-coupler may be at or proximate the second longitudinal surface andmay in-couple the first set of light signals by transmission.

At 602, the first set of light signals are propagated along a length ofthe volume of optically transparent material by total internalreflection between the first longitudinal surface and the secondlongitudinal surface.

At 603, a refractive index of the liquid crystal out-coupler ismodulated to a first refractive index by the controller. The controllermay modulate the refractive index of the liquid crystal out-coupler byaltering a voltage (or another modulating signal) applied to the liquidcrystal in-coupler. The liquid crystal may operate in a positive modewherein a higher voltage results in a higher opacity, or a negative modewherein a higher voltage results in a lower opacity. The liquid crystalout-coupler may comprise multiple independently modulatable regionswhich may be modulated by the controller to each have a respective firstrefractive index, wherein the refractive index of each respective regionmay be different from or the same as the refractive indices of the otherregions. The controller may be communicatively coupled to a processorwhich modulates the output of signals from the controller. The processormay be communicatively coupled to a non-transitory processor-readablestorage medium and the processor may execute data and/or instructionfrom the non-transitory processor readable storage medium to modulatethe controller.

At 604, the first set of light signals is output, for example towardsthe eye of the user, by the liquid crystal out-coupler, wherein anoutput path of the first set of light signals is dependent on therefractive index of the liquid crystal out-coupler. That is, the path ofthe light signals is altered (or remains unaltered) in response to therefractive index of the liquid crystal out-coupler, resulting in thelight signals being steered by the liquid crystal out-coupler. The pathof an individual light signal may also be dependent on the wavelength ofthe light signal, the location of incidence of the light signal on theliquid crystal out-coupler, and/or the angle of incidence of the lightsignal on the liquid crystal out-coupler. The light signals are outputon a path that will result in a desired image or part of an image at adesired location, for example at the eye of the user. If the liquidcrystal out-coupler comprises multiple independently modulatableregions, the path of an individual light signal is dependent on themodulatable region upon which the individual light signal is incident.The liquid crystal out-coupler may be at or proximate the firstlongitudinal surface and may out-couple the first set of light signalsby reflection, or the liquid crystal out-coupler may be at or proximatethe second longitudinal surface and may out-couple the first set oflight signals by transmission.

Method 600 may further include repeating acts 601, 602, 603, 604, and605 with a second set of light signals, wherein the controller modulatesthe liquid crystal in-coupler to have a second refractive index, or ifthe liquid crystal in-coupler has multiple independently modulatableregions, a second set of refractive indices. This may be repeated forother sets of light signals. If each set of light signals is a singlelight signal, an image or other desired pattern of light may be createdby modulating the refractive index of the liquid crystal in-coupler tosteer further sets of light signals as they are generated over time.That is, the refractive index of the liquid crystal in-coupler mayenable “scanning” of subsequent single light signals to create an image(e.g., raster scanning). If each of light signals comprises multiplelight signals, modulating the refractive index of the liquid crystalin-coupler may steer an exit pupil of an image (or portion of an image)or other desired pattern created by the multiple light signals.

Alternatively, a waveguide may include both a liquid crystal in-couplerand a liquid crystal out-coupler, wherein both the liquid crystalin-coupler and the liquid crystal out-coupler are communicativelycoupled to a controller (either the same controller or two distinctcontrollers). The method for operating such an optical device wouldinclude modulating the refractive indices of both the liquid crystalin-coupler and the liquid crystal out-coupler by the respectivecontrollers to steer both the in-coupling paths of light signals and theout-coupling paths of light signals to create an image or part of animage.

FIG. 7 is a schematic diagram of a wearable heads-up display (WHUD) 700with a waveguide with a liquid crystal in-coupler 720 and a liquidcrystal out-coupler 770 in accordance with the present systems, devices,and methods. WHUD 700 includes a support structure 780 with the shapeand appearance of a pair of eyeglasses, and eyeglass lens 781 carried bysupport structure 780, a projector 782 having at least one light sourceand carried by support structure 780, and a waveguide. Projector 782includes at least one light source to generate light signals. Projector782 may be a scanning projector (e.g., a scanning laser projector) andmay include a scanner to scan the light signals, such as a MEMS scanmirror. The waveguide includes a volume of optically transparentmaterial 710, liquid crystal in-coupler 720, and liquid crystalout-coupler 770. Liquid crystal in-coupler 720 and liquid crystalout-coupler 770 are communicatively coupled to a controller (e.g.,circuitry, micro-controller) 730 (communicative coupling not shown toreduce clutter). Controller 730 and projector 782 may be communicativelycoupled to a processor (e.g., microprocessor) which modulates the outputof signals from controller 730 and the generation of light signals byprojector 782. The processor may be communicatively coupled to anon-transitory processor-readable storage medium (e.g., memory circuitssuch as ROM, RAM, FLASH, EEPROM, memory registers, magnetic disks,optical disks, other storage) and the processor may execute data and/orinstruction from the non-transitory processor readable storage medium tomodulate controller 730 and projector 782. Controller 730 and projector782 may each be communicatively coupled to respective processor. WHUD700 operates as follows.

The at least one light source of projector 782 generates a first set oflight signals. The first set of light signals may be a single beam oflight or may be multiple light signals. The first set of light signalsis directed towards and is incident on liquid crystal in-coupler 720.The first set of light signals may be directed towards liquid crystalin-coupler 720 by a scanner, such as a MEMS mirror. Liquid crystalin-coupler 720 is modulated to have a first refractive index bycontroller 730 (this modulation may before generation of the lightsignals or incidence of the light signals on liquid crystal in-coupler730). The first set of light signals are in-coupled into the volume ofoptically transparent material by liquid crystal in-coupler 720. Thatis, the path of the first set of light signals is altered (or remainsunaltered) in response to the refractive index of liquid crystalin-coupler 720, resulting in the light signals being steered by liquidcrystal in-coupler 720. The first set of light signals is in-coupled ona path that will eventually result in a desired image or part of animage at the eye of a user. The path of an individual light signal maybe dependent on the wavelength of the light signal, the location ofincidence of the light signal on liquid crystal in-coupler 720, and/orthe angle of incidence of the light signal on liquid crystal in-coupler720. If liquid crystal in-coupler 720 comprises multiple independentlymodulatable regions the path of an individual light signal is dependenton the modulatable region upon which the individual light signal isincident. The first set of light signals is propagated down a length ofvolume of optically transparent material 710 by total internalreflection between a first longitudinal surface of volume of opticallytransparent material 710 and a second longitudinal surface of volume ofoptically transparent material 710. Upon incidence of the first set oflight signals on liquid crystal out-coupler 770, the first set of lightsignals it output from the waveguide towards an eye of the user. Thatis, the path of the first set of light signals is altered (or remainsunaltered) in response to the refractive index of liquid crystalout-coupler 770, resulting in the first set of light signals beingsteered by liquid crystal out-coupler 770. The first set of lightsignals is output on a path that will result in a desired image or partof an image at the eye of the user. The path of an individual lightsignal may be dependent on the wavelength of the light signal, thelocation of incidence of the light signal on the liquid crystalout-coupler, and/or the angle of incidence of the light signal on theliquid crystal out-coupler. If liquid crystal out-coupler 770 comprisesmultiple independently modulatable regions the path of an individuallight signal is dependent on the modulatable region upon which theindividual light signal is incident. The projector then generates asecond set of light signals which are in-coupled into volume ofoptically transparent material 710 and out-coupled out of the waveguidein the same manner as the first set of light signals but wherein thecontroller modulates the refractive indices of liquid crystal in-coupler720 and liquid crystal out-coupler 770 to create the desired image orportion of an image at the eye of the user. This process can be repeatedn times, where n is any positive integer. When a first set of lightsignals displays an entire image at the eye of the user, repeating theprocess n times may result in displaying several images at the eye ofthe user over time and may be used to steer the exit pupil of thedisplay. An eyetracker may be used to determine how the refractiveindices of liquid crystal in-coupler 720 and liquid crystal out-coupler770 may be modulated to steer the exit pupil. When a first set of lightsignals only displays a portion of an image at the eye of the user andsubsequent sets of light signals display respective different portionsof the same image, repeating the process n times may result indisplaying portions of an image to create a total image at the eye ofthe user. WHUD 700 is shown with display apparatus (projector andwaveguide) on only one side but could, for example, have a display foreach eye of the user. Images provide to each side may differ from oneanother to, for instance, create a sense of depth.

FIG. 8 is a schematic diagram of a WHUD 800 with a projector 882, aliquid crystal in-coupler 820 with multiple modulatable regions 821,822, and 823 and a liquid crystal out-coupler 870 with multiplemodulatable regions 871, 872, and 873 in accordance with the presentsystems, devices, and methods. Optical device 800 includes a waveguidecomprising a volume of optically transparent material 810 having a firstlongitudinal surface 811 positioned opposite a second longitudinalsurface 812 across a width 813 of volume of optically transparentmaterial 810, a liquid crystal in-coupler 820 with multiple modulatableregions 821, 822, and 823, a liquid crystal out-coupler 870 withmultiple modulatable regions 871, 872, and 873, and a controller (e.g.,circuitry, micro-controller) 830 communicatively coupled to both liquidcrystal in-coupler 820 and liquid crystal out-coupler 870. Projector 882includes at least one light source to generate light signals, includinglight signals 851, 852, and 853. Projector 882 may be a scanningprojector (e.g., a scanning laser projector) and may include a scannerto scan the light signals, such as a MEMS scan mirror. Controller 830modulates each of modulatable regions 821, 822, and 823, independentlyand may be separately communicatively coupled to each modulatable region(controller 830 is shown as having only one coupling to each of liquidcrystal in-coupler 820 and liquid crystal out-coupler 870 to reduceclutter). Controller 830 is shown in this configuration solely forclarity and in an actual implementation would not be so located.Controller 830 may be communicatively coupled to a processor (e.g.,microprocessor) which modulates the output of signals from controller830. The processor may be communicatively coupled to a non-transitoryprocessor-readable storage medium (e.g., memory circuits such as ROM,RAM, FLASH, EEPROM, memory registers, magnetic disks, optical disks,other storage) and the processor may execute data and/or instructionfrom the non-transitory processor readable storage medium to modulatecontroller 830. In FIG. 8, liquid crystal in-coupler 820 and liquidcrystal out-coupler 870 each have three distinct, modulatable regionsbut in other implementations there may be any number of distinct,modulatable regions greater than one.

The operation of WHUD 800 is similar to the operation of optical device400 which the addition of projector 882 and an eye of a user 890.Projector 882 generates a first set of light signals which are directedtowards liquid crystal in-coupler 820. Light signals 851, 852, and 853follow the same path through liquid crystal in-coupler 820, volume ofoptically transparent material 810, and liquid crystal out-coupler 870as light signals 451, 452, and 453 in FIG. 4 and the same modulation ofmodulatable regions 821, 822, 823, 871, 872, and 873 by controller 830occurs. Light signals 851, 852, and 853 are out-coupled by liquidcrystal out-coupler 870 towards eye 890 (eye 890 is not shown to scale).The paths of light signals 851, 852, and 853 are dependent on therefractive indices of the respective modulatable regions 821, 822, 823,871, 872, and 873 upon which light signals 851, 852, and 853 areincident. The paths of light signals 851, 852, and 852 may also bedependent on the wavelengths of the light signals, the locations ofincidence of the light signals on liquid crystal in-coupler 820 andliquid crystal out-coupler 870, and the angles of incidence of thelights signals on liquid crystal in-coupler 820 and liquid crystalout-coupler 870.

FIG. 9 is a flow diagram of a method 900 of operating a wearableheads-up display (WHUD) with a liquid crystal in-coupler in accordancewith the present systems, devices, and methods. The WHUD of FIG. 9includes a support structure which in use is worn on the head of userand which carries a projector and a waveguide. The projector includes atleast one light source to generate light signals. The projector may be ascanning projector which includes a scanner operable to spatially scanthe light signals over an area, such as a MEMS scan mirror. Thewaveguide includes a volume of optically transparent material having afirst longitudinal surface positioned opposite a second longitudinalsurface across a width of the volume of optically transparent material,a liquid crystal in-coupler, a controller (e.g., circuitry,micro-controller) communicatively coupled to the liquid crystalin-coupler, and an out-coupler. Method 900 includes acts 901, 902, 903,904, and 905, though those of skill in the art will appreciate that inalternative embodiments certain acts may be omitted and/or additionalacts may be added. Those of skill in the art will also appreciate thatthe illustrated order of the acts is shown for exemplary purposes onlyand may change in alternative embodiment.

At 901, at least one light source of the projector generates a first setof light signals. The first set of light signals may be a single lightsignal or may be multiple light signals. The light signals may bedirected away from the projector via scanning by the scanner (e.g., MEMSscan mirror, rotating mirror, pivoting mirror).

At 902, a refractive index of the liquid crystal in-coupler is modulatedto a first refractive index by the controller. The controller maymodulate the refractive index of the liquid crystal in-coupler byaltering a voltage (or another modulating signal) applied to the liquidcrystal in-coupler. The liquid crystal may operate in a positive modewherein a higher voltage results in a higher opacity, or a negative modewherein a higher voltage results in a lower opacity. The liquid crystalin-coupler may comprise multiple independently modulatable regions whichmay be modulated by the controller to each have a respective firstrefractive index, wherein the refractive index of each respective regionmay be different from or the same as the refractive indices of the otherregions. The controller may be communicatively coupled to a processor(e.g., microprocessor) which modulates the output of signals from thecontroller. The processor may be communicatively coupled to anon-transitory processor-readable storage medium (e.g., memory circuitssuch as ROM, RAM, FLASH, EEPROM, memory registers, magnetic disks,optical disks, other storage) and the processor may execute data and/orinstruction from the non-transitory processor readable storage medium tomodulate the controller.

At 903, the first set of light signals is in-coupled into the volume ofoptically transparent material of the waveguide, wherein a path (orpaths) of the first set of light signals within the volume of opticallytransparent material is dependent on the first refractive index of theliquid crystal in-coupler. That is, the path of the light signals isaltered (or remains unaltered) in response to the refractive index ofthe liquid crystal in-coupler, resulting in the light signals beingsteered by the liquid crystal in-coupler. The path of an individuallight signal may also be dependent on the wavelength of the lightsignal, the location of incidence of the light signal on the liquidcrystal in-coupler, and/or the angle of incidence of the light signal onthe liquid crystal in-coupler. The light signals are in-coupled on apath that will eventually result in a desired image or part of an imageat the eye of a user. If the liquid crystal in-coupler comprisesmultiple independently modulatable regions the path of an individuallight signal is dependent on the modulatable region upon which theindividual light signal is incident. The liquid crystal in-coupler maybe present on the exterior of the volume of optically transparentmaterial or may be located inside the volume of optically transparentmaterial. If located inside the volume of optically transparentmaterial, the liquid crystal in-coupler may be at or proximate the firstlongitudinal surface of the second longitudinal surface, or may beembedded within the volume of optically transparent material not at orproximate a surface.

At 904, the first set of light signals are propagated along a length ofthe volume of optically transparent material by total internalreflection between the first longitudinal surface and the secondlongitudinal surface.

At 905, the first set of light signals are output from the waveguidetowards an eye of the user by the out-coupler. The first set of lightsignals are output from the waveguide on a path that creates the desiredimage or part of an image at the eye of the user. The output path of anindividual light signal may depend on the wavelength of the lightsignal, the location of incidence of the light signal on theout-coupler, and/or the angle of incidence of the light signals on theout-coupler. The out-coupler may be at or proximate the firstlongitudinal surface and may out-couple the first set of light signalsby reflection or the out-coupler may be at or proximate the secondlongitudinal surface and may out-couple the first set of light signalsby transmission.

Method 900 may further include repeating acts 901, 902, 903, 904, and905 with a second set of light signals, wherein the controller modulatesthe liquid crystal in-coupler to have a second refractive index, or ifthe liquid crystal in-coupler has multiple independently modulatableregions, a second set of refractive indices. This may be repeated forother sets of light signals. If each set of light signals is a singlelight signal, an image or other desired pattern of light may be createdby modulating the refractive index of the liquid crystal in-coupler tosteer further sets of light signals as they are generated over time.That is, the refractive index of the liquid crystal in-coupler mayenable “scanning” of subsequent single light signals to create an image(e.g., raster scanning). If each set of light signals comprises multiplelight signals, modulating the refractive index of the liquid crystalin-coupler may steer an exit pupil of an image (or portion of an image)or other desired pattern created by the multiple light signals. In someimplementations, the out-coupler may be a liquid crystal out-couplerwhich is communicatively coupled to the controller (or may becommunicatively coupled to a second, distinct controller) and the methodmay further include modulating the refractive index of the liquidcrystal out-coupler to a third refractive index (the third refractiveindex may be the same as either the first or second refractive index andmay be different from both the first or second refractive index) andout-coupling a set of light signals on output path(s) which aredependent on the refractive index of the liquid crystal out-coupler. Theoutput paths of the light signals may also be dependent on thewavelength of the light signals, the location of incidence of the lightsignals on the liquid crystal out-coupler, and/or the angle of incidenceof the light signals on the liquid crystal out-coupler.

FIG. 10 is a flow diagram of a method 1000 of operating a wearableheads-up display with an waveguide with a liquid crystal out-coupler inaccordance with the present systems, devices, and methods. The WHUD ofFIG. 10 includes a support structure which in use is worn on the head ofuser and which carries a projector and an waveguide. The projectorincludes at least one light source to generate light signals. Theprojector may be a scanning projector which includes a scanner operableto spatially scan the light signals over an area, such as a MEMS scanmirror. The waveguide includes a volume of optically transparentmaterial having a first longitudinal surface positioned opposite asecond longitudinal surface across a width of volume of opticallytransparent material, an in-coupler, a liquid crystal out-coupler, and acontroller (e.g., circuitry, micro-controller) communicatively coupledto the liquid crystal out-coupler. Method 1000 includes acts 1001, 1002,1003, 1004, and 1005, though those of skill in the art will appreciatethat in alternative embodiments certain acts may be omitted and/oradditional acts may be added. Those of skill in the art will alsoappreciate that the illustrated order of the acts is shown for exemplarypurposes only and may change in alternative embodiment.

At 1001, at least one light source of the projector generates a firstset of light signals. The first set of light signals may be a singlelight signal or may be multiple light signals. The light signals may bedirected away from the projector via scanning by the scanner (e.g., MEMSscan mirror, rotating mirror, pivoting mirror).

At 1002, the first set of light signals are in-coupled into the volumeof optically transparent material by the in-coupler. That is, the firstset of light signals are in-coupled into the volume of opticallytransparent material on the desired path to eventually create a desiredimage or part of an image at the eye of the user. The path of anindividual light signal may depend on the wavelength of the lightsignal, the location of incidence of the light signal on theout-coupler, and/or the angle of incidence of the light signals on theout-coupler. The in-coupler may be at or proximate the firstlongitudinal surface and may in-couple the first set of light signals byreflection or the in-coupler may be at or proximate the secondlongitudinal surface and may in-couple the first set of light signals bytransmission.

At 1003, the first set of light signals are propagated along a length ofthe volume of optically transparent material by total internalreflection between the first longitudinal surface and the secondlongitudinal surface.

At 1004, a refractive index of the liquid crystal out-coupler ismodulated to a first refractive index by the controller. The controllermay modulate the refractive index of the liquid crystal out-coupler byaltering a voltage (or another modulating signal) applied to the liquidcrystal in-coupler. The liquid crystal may operate in a positive modewherein a higher voltage results in a higher opacity, or a negative modewherein a higher voltage results in a lower opacity. The liquid crystalout-coupler may comprise multiple independently modulatable regionswhich may be modulated by the controller to each have a respective firstrefractive index, wherein the refractive index of each respective regionmay be different from or the same as the refractive indices of the otherregions. The controller may be communicatively coupled to a processor(e.g., microprocessor) which modulates the output of signals from thecontroller. The processor may be communicatively coupled to anon-transitory processor-readable storage medium (e.g., memory circuitssuch as ROM, RAM, FLASH, EEPROM, memory registers, magnetic disks,optical disks, other storage) and the processor may execute data and/orinstruction from the non-transitory processor readable storage medium tomodulate the controller.

At 1005, the first set of light signals is output towards the eye of theuser by the liquid crystal out-coupler, wherein an output path of thefirst set of light signals is dependent on the refractive index of theliquid crystal out-coupler. That is, the path of the light signals isaltered (or remains unaltered) in response to the refractive index ofthe liquid crystal out-coupler, resulting in the light signals beingsteered by the liquid crystal out-coupler. The path of an individuallight signal may be dependent on the wavelength of the light signal, thelocation of incidence of the light signal on the liquid crystalout-coupler, and/or the angle of incidence of the light signal on theliquid crystal out-coupler. The light signals are output on a path thatwill result in a desired image or part of an image at the eye of theuser. If the liquid crystal out-coupler comprises multiple independentlymodulatable regions the path of an individual light signal is dependenton the modulatable region upon which the individual light signal isincident. The liquid crystal out-coupler may be at or proximate thefirst longitudinal surface and may out-couple the first set of lightsignals by reflection, or the liquid crystal out-coupler may be at orproximate the second longitudinal surface and may out-couple the firstset of light signals by transmission.

Method 1000 may further include repeating acts 1001, 1002, 1003, 1004,and 1005 with a second set of light signals, wherein the controllermodulates the liquid crystal in-coupler to have a second refractiveindex, or if the liquid crystal in-coupler has multiple independentlymodulatable regions, a second set of refractive indices. This may berepeated for other sets of light signals. If each set of light signalsis a single light signal, an image or other desired pattern of light maybe created by modulating the refractive index of the liquid crystalin-coupler to steer further sets of light signals as they are generatedover time. That is, the refractive index of the liquid crystalin-coupler may enable “scanning” of subsequent single light signals tocreate an image (e.g., raster scanning). If each set of light signalscomprises multiple light signals, modulating the refractive index of theliquid crystal in-coupler may steer an exit pupil of an image (orportion of an image) or other desired pattern created by the multiplelight signals.

Alternatively, a WHUD may include both a liquid crystal in-coupler and aliquid crystal out-coupler, wherein both the liquid crystal in-couplerand the liquid crystal out-coupler are communicatively coupled to acontroller (either the same controller or two distinct controllers). Themethod for operating such an waveguide would include modulating therefractive indices of both the liquid crystal in-coupler and the liquidcrystal out-coupler by the respective controllers to steer both thein-coupling paths of light signals and the out-coupling paths of lightsignals to create an image or part of an image at the eye of a user.

Throughout this specification and the drawings various in-coupling andout-coupling paths are discussed and shown. These paths are meant to beexemplary and are not meant to show any actual paths or to representachievable ranges of directions which light signals can travel in uponin-coupling or out-coupling.

The various embodiments described herein provide systems, devices, andmethods for steering light with waveguides. Such are particularlywell-suited for use as or in the transparent combiner of wearableheads-up displays (“WHUDs”) in order to enable the WHUDs to adopt moreaesthetically-pleasing styles and to increase the relative size of thedisplay. Examples of WHUD systems, devices, and methods that areparticularly well-suited for use in conjunction with the presentsystems, devices, and methods for curved lenses with optical waveguidesare described in, for example, U.S. Non-Provisional patent applicationSer. No. 15/167,458, U.S. Non-Provisional patent application Ser. No.15/167,472, and U.S. Non-Provisional patent application Ser. No.15/167,484.

In some implementations, an optical waveguide may terminate at theout-coupling optical grating because there is no desire to propagatelight within the optical waveguide beyond that point. However, this canresult in a visible seam within or upon the eyeglass lens where theoptical waveguide ends. In order to avoid this seam, in someimplementations, an optical waveguide may be extended beyond theout-coupling optical grating to the far edge of an eyeglass lens eventhough there is no intention to propagate light within the opticalwaveguide beyond the out-coupling optical grating.

In some implementations, an optical waveguide may have cladding on theexterior of the waveguide at the first and second longitudinal surfaces,except where the in-coupler and out-coupler are located, wherein thecladding has a refractive index which enables total internal reflectionwithin the waveguide.

Some of the optical waveguides described herein (particularly those thatemploy curvature) may introduce optical distortions in displayed images.In accordance with the present systems, devices, and methods, suchoptical distortions may be corrected (i.e., compensated for) in thesoftware that drives the display engine. For example, the geometricaloutput of the transparent combiner may be measured without anycompensation measure in place and a reverse transform of such output maybe applied in the generation of light by the display light source.

The relative positions of optical waveguides within lenses/combinersshown herein are used for illustrative purposes only. In someimplementations, it may be advantageous for an optical waveguide to bepositioned centrally within a combiner, whereas in other implementationsit may be advantageous for an optical waveguide to be positionedoff-center. In particular, it may be advantageous for an opticalwaveguide to couple to the corner of the support structure/glasses framewhere the temple of the glasses frame meets the rims, because this is anadvantageous location to route display light from a scanning laserprojector or microdisplay with minimal impact on form factor.

The various embodiments described herein generally reference andillustrate a single eye of a user (i.e., monocular applications), but aperson of skill in the art will readily appreciate that the presentsystems, devices, and methods may be duplicated in a WHUD in order toprovide scanned laser projection and scanned laser eye tracking for botheyes of the user (i.e., binocular applications).

The WHUDs described herein may include one or more sensor(s) (e.g.,microphone, camera, thermometer, compass, and/or others) for collectingdata from the user's environment. For example, one or more camera(s) maybe used to provide feedback to the processor of the wearable heads-updisplay and influence where on the transparent display(s) any givenimage should be displayed.

The WHUDs described herein may include one or more on-board powersources (e.g., one or more battery(ies)), a wireless transceiver forsending/receiving wireless communications, and/or a tethered connectorport for coupling to a computer and/or charging the one or more on-boardpower source(s). Throughout this specification and the appended claimsthe term “communicative” as in “communicative pathway,” “communicativecoupling,” and in variants such as “communicatively coupled,” isgenerally used to refer to any engineered arrangement for transferringand/or exchanging information. Exemplary communicative pathways include,but are not limited to, electrically conductive pathways (e.g.,electrically conductive wires, electrically conductive traces), magneticpathways (e.g., magnetic media), and/or optical pathways (e.g., opticalfiber), and exemplary communicative couplings include, but are notlimited to, electrical couplings, magnetic couplings, and/or opticalcouplings.

Throughout this specification and the appended claims, infinitive verbforms are often used. Examples include, without limitation: “to detect,”“to provide,” “to transmit,” “to communicate,” “to process,” “to route,”and the like. Unless the specific context requires otherwise, suchinfinitive verb forms are used in an open, inclusive sense, that is as“to, at least, detect,” to, at least, provide,” “to, at least,transmit,” and so on.

The above description of illustrated embodiments, including what isdescribed in the Abstract, is not intended to be exhaustive or to limitthe embodiments to the precise forms disclosed. Although specificembodiments of and examples are described herein for illustrativepurposes, various equivalent modifications can be made without departingfrom the spirit and scope of the disclosure, as will be recognized bythose skilled in the relevant art. The teachings provided herein of thevarious embodiments can be applied to other portable and/or wearableelectronic devices, not necessarily the exemplary wearable electronicdevices generally described above.

For instance, the foregoing detailed description has set forth variousembodiments of the devices and/or processes via the use of blockdiagrams, schematics, and examples. Insofar as such block diagrams,schematics, and examples contain one or more functions and/oroperations, it will be understood by those skilled in the art that eachfunction and/or operation within such block diagrams, flowcharts, orexamples can be implemented, individually and/or collectively, by a widerange of hardware, software, firmware, or virtually any combinationthereof. In one embodiment, the present subject matter may beimplemented via Application Specific Integrated Circuits (ASICs).However, those skilled in the art will recognize that the embodimentsdisclosed herein, in whole or in part, can be equivalently implementedin standard integrated circuits, as one or more computer programsexecuted by one or more computers (e.g., as one or more programs runningon one or more computer systems), as one or more programs executed by onone or more controllers (e.g., microcontrollers) as one or more programsexecuted by one or more processors (e.g., microprocessors, centralprocessing units, graphical processing units), as firmware, or asvirtually any combination thereof, and that designing the circuitryand/or writing the code for the software and or firmware would be wellwithin the skill of one of ordinary skill in the art in light of theteachings of this disclosure.

When logic is implemented as software and stored in memory, logic orinformation can be stored on any processor-readable medium for use by orin connection with any processor-related system or method. In thecontext of this disclosure, a memory is a processor-readable medium thatis an electronic, magnetic, optical, or other physical device or meansthat contains or stores a computer and/or processor program. Logicand/or the information can be embodied in any processor-readable mediumfor use by or in connection with an instruction execution system,apparatus, or device, such as a computer-based system,processor-containing system, or other system that can fetch theinstructions from the instruction execution system, apparatus, or deviceand execute the instructions associated with logic and/or information.

In the context of this specification, a “non-transitoryprocessor-readable medium” can be any element that can store the programassociated with logic and/or information for use by or in connectionwith the instruction execution system, apparatus, and/or device. Theprocessor-readable medium can be, for example, but is not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus or device. More specific examples (anon-exhaustive list) of the computer readable medium would include thefollowing: a portable computer diskette (magnetic, compact flash card,secure digital, or the like), a random access memory (RAM), a read-onlymemory (ROM), an erasable programmable read-only memory (EPROM, EEPROM,or Flash memory), a portable compact disc read-only memory (CDROM),digital tape, and other non-transitory media.

The various embodiments described above can be combined to providefurther embodiments. To the extent that they are not inconsistent withthe specific teachings and definitions herein, all of the U.S. patents,U.S. patent application publications, U.S. patent applications, foreignpatents, foreign patent applications and non-patent publicationsreferred to in this specification and/or listed in the Application DataSheet which are owned by Thalmic Labs Inc., including but not limitedto: U.S. Non-Provisional patent application Ser. No. 15/167,458, U.S.Non-Provisional patent application Ser. No. 15/167,472, U.S.Non-Provisional patent application Ser. No. 15/167,484, U.S. patentapplication Ser. No. 15/381,883, US Patent Application Publication No.2017-0068095, U.S. Provisional Application Ser. No. 62/557,551, and U.S.Provisional Application Ser. No. 62/557,554, are incorporated herein byreference, in their entirety. Aspects of the embodiments can bemodified, if necessary, to employ systems, circuits and concepts of thevarious patents, applications and publications to provide yet furtherembodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

1. A wearable heads-up display (WHUD) comprising: a support structurethat in use is worn on the head of a user; a projector to generate lightsignals, the projector comprising at least one light source; an opticalwaveguide comprising a volume of optically transparent material topropagate light signals by total internal reflection, wherein the volumeof optically transparent material has a first longitudinal surface and asecond longitudinal surface, the second longitudinal surface oppositethe first longitudinal surface across a width of the volume of opticallytransparent material; an in-coupler; a liquid crystal out-coupler totunably steer light signals; and a controller communicatively coupled tothe liquid crystal out-coupler, wherein a refractive index of the liquidcrystal out-coupler is modulatable in response to signals from thecontroller.
 2. The WHUD of claim 1 wherein the liquid crystalout-coupler comprises a single modulatable region.
 3. The WHUD of claim1 wherein the liquid crystal out-coupler comprises at least twodistinct, independently modulatable regions.
 4. The WHUD of claim 1further comprising a processor communicatively coupled to the projectorto modulate the generation of light signals and communicatively coupledto the controller to modulate the output of signals from the controller.5. The WHUD of claim 1 further comprising a processor communicativelycoupled to the projector to modulate the generation of light signals. 6.The WHUD of claim 1 further comprising a processor communicativelycoupled to the controller to modulate the output of signals from thecontroller.